/* minicom.cpp 
        A simple demonstration minicom client with Boost asio 
        
        Parameters: 
                baud rate 
                serial port (eg /dev/ttyS0 or COM1) 
                
        To end the application, send Ctrl-C on standard input 
*/ 

#include <deque> 
#include <iostream> 
#include <boost/bind.hpp> 
#include <boost/asio.hpp> 
#include <boost/asio/serial_port.hpp> 
#include <boost/thread.hpp> 
#include <boost/lexical_cast.hpp> 
#include <boost/date_time/posix_time/posix_time_types.hpp> 

#ifdef POSIX 
#include <termios.h> 
#endif 

using namespace std; 

class minicom_client 
{ 
public: 
        minicom_client(boost::asio::io_service& io_service, unsigned int baud, const string& device) 
                : active_(true), 
                  io_service_(io_service), 
                  serialPort(io_service, device) 
        { 
                if (not serialPort.is_open()) 
                { 
                        cerr << "Failed to open serial port\n"; 
                        return; 
                } 
                boost::asio::serial_port_base::baud_rate baud_option(baud); 
                serialPort.set_option(baud_option); // set the baud rate after the port has been opened 
                read_start(); 
        } 
        
        void write(const char msg) // pass the write data to the do_write function via the io service in the other thread 
        { 
                io_service_.post(boost::bind(&minicom_client::do_write, this, msg)); 
        } 
        
        void close() // call the do_close function via the io service in the other thread 
        { 
                io_service_.post(boost::bind(&minicom_client::do_close, this, boost::system::error_code())); 
        } 

        bool active() // return true if the socket is still active 
        { 
                return active_; 
        } 

private: 

        static const int max_read_length = 512; // maximum amount of data to read in one operation 
        
        void read_start(void) 
        { // Start an asynchronous read and call read_complete when it completes or fails 
                serialPort.async_read_some(boost::asio::buffer(read_msg_, max_read_length), 
                        boost::bind(&minicom_client::read_complete, 
                                this, 
                                boost::asio::placeholders::error, 
                                boost::asio::placeholders::bytes_transferred)); 
        } 
        
        void read_complete(const boost::system::error_code& error, size_t bytes_transferred) 
        { // the asynchronous read operation has now completed or failed and returned an error 
                if (!error) 
                { // read completed, so process the data 
                        cout.write(read_msg_, bytes_transferred); // echo to standard output 
                        read_start(); // start waiting for another asynchronous read again 
                } 
                else 
                        do_close(error); 
        } 
        
        void do_write(const char msg) 
        { // callback to handle write call from outside this class 
                bool write_in_progress = !write_msgs_.empty(); // is there anything currently being written? 
                write_msgs_.push_back(msg); // store in write buffer 
                if (!write_in_progress) // if nothing is currently being written, then start 
                        write_start(); 
        } 
        
        void write_start(void) 
        { // Start an asynchronous write and call write_complete when it completes or fails 
                boost::asio::async_write(serialPort, 
                        boost::asio::buffer(&write_msgs_.front(), 1), 
                        boost::bind(&minicom_client::write_complete, 
                                this, 
                                boost::asio::placeholders::error)); 
        } 
        
        void write_complete(const boost::system::error_code& error) 
        { // the asynchronous read operation has now completed or failed and returned an error 
                if (!error) 
                { // write completed, so send next write data 
                        write_msgs_.pop_front(); // remove the completed data 
                        if (!write_msgs_.empty()) // if there is anthing left to be written 
                                write_start(); // then start sending the next item in the buffer 
                } 
                else 
                        do_close(error); 
        } 
        
        void do_close(const boost::system::error_code& error) 
        { // something has gone wrong, so close the socket & make this object inactive 
                if (error == boost::asio::error::operation_aborted) // if this call is the result of a timer cancel() 
                        return; // ignore it because the connection cancelled the timer 
                if (error) 
                        cerr << "Error: " << error.message() << endl; // show the error message 
                else 
                        cout << "Error: Connection did not succeed.\n"; 
                cout << "Press Enter to exit\n"; 
                serialPort.close(); 
                active_ = false; 
        } 

private: 
        bool active_; // remains true while this object is still operating 
        boost::asio::io_service& io_service_; // the main IO service that runs this connection 
        boost::asio::serial_port serialPort; // the serial port this instance is connected to 
        char read_msg_[max_read_length]; // data read from the socket 
        deque<char> write_msgs_; // buffered write data 
}; 

int main(int argc, char* argv[]) 
{ 
// on Unix POSIX based systems, turn off line buffering of input, so cin.get() returns after every keypress 
// On other systems, you'll need to look for an equivalent 
#ifdef POSIX 
        termios stored_settings; 
        tcgetattr(0, &stored_settings); 
        termios new_settings = stored_settings; 
        new_settings.c_lflag &= (~ICANON); 
        new_settings.c_lflag &= (~ISIG); // don't automatically handle control-C 
        tcsetattr(0, TCSANOW, &new_settings); 
#endif 
        try 
        { 
                if (argc != 3) 
                { 
                        cerr << "Usage: minicom <baud> <device>\n"; 
                        return 1; 
                } 
                boost::asio::io_service io_service; 
                // define an instance of the main class of this program 
                minicom_client c(io_service, boost::lexical_cast<unsigned int>(argv[1]), argv[2]); 
                // run the IO service as a separate thread, so the main thread can block on standard input 
                boost::thread t(boost::bind(&boost::asio::io_service::run, &io_service)); 
                while (c.active()) // check the internal state of the connection to make sure it's still running 
                { 
                        char ch; 
                        cin.get(ch); // blocking wait for standard input 
                        if (ch == 3) // ctrl-C to end program 
                                break; 
                        c.write(ch); 
                } 
                c.close(); // close the minicom client connection 
                t.join(); // wait for the IO service thread to close 
        } 
        catch (exception& e) 
        { 
                cerr << "Exception: " << e.what() << "\n"; 
        } 
#ifdef POSIX // restore default buffering of standard input 
        tcsetattr(0, TCSANOW, &stored_settings); 
#endif 
        return 0; 
} 
